CN101425948B - Industrial wireless network access industrial Ethernet, multi-protocol gateway of field bus and protocol conversion method - Google Patents

Abstract

The invention relates to a multi-protocol gateway and a protocol conversion method for an IEEE802.15.4a-based industrial wireless network accessing MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus. This multi-protocol gateway includes microprocessor, MODBUS/TCP master station, IEEE802.15.4a wireless master station, PROFIBUS-DP slave station, externally expanded SDRAM memory and FLASH memory, RJ45 network port, 485 physical layer interface, USB interface; The connection method is centered on the microprocessor, the DM9161EP Ethernet physical layer interface chip is expanded through the MDIO interface, the PROFIBUS-DP protocol chip SPC3 is connected through the internal bus, the NA1TR8 wireless protocol chip is connected through the SPI bus, and the USB interface is expanded externally. The protocol conversion method of the multi-protocol gateway is controlled by a microprocessor to realize the protocol conversion between the three networks. The present invention considers the current situation of the current wired field bus/industrial Ethernet as the mainstay, and also takes into account the seamless connection with the wireless network frontier technology, and realizes a wired/wireless heterogeneous control network that meets industrial real-time requirements and open data communication gateway.

Description

Multi-protocol gateway and protocol conversion method for industrial wireless network to access industrial Ethernet and field bus

technical field

The invention relates to a multi-protocol gateway and a protocol conversion method that introduces an industrial wireless network based on IEEE802.15.4a into MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus, involves conversion of various communication protocols, and belongs to field bus control technology field.

technical background

The field bus is the underlying communication network used in the production and manufacturing sites. It realizes the bidirectional serial multi-node digital communication between computerized on-site measurement and control instruments or equipment, and has the characteristics of real-time and high stability. Since the International Electrotechnical Commission (IEC) announced and passed the IEC61158 fieldbus standard in 2000, there are now more than ten fieldbus standards.

Ethernet is a local area network commonly used in the commercial field. Combining with the TCP/IP protocol, it forms the basis of the Internet and becomes the de facto standard in network applications. This also enables the fieldbus control system to realize factory monitoring through the integration of Ethernet and enterprise information networks. Integration has become the general trend.

Currently, fieldbus and industrial Ethernet technologies are widely used in industrial production. However, due to the complexity of the process industry, wired networks cannot meet the measurement and control requirements in harsh environments, and wireless network technology provides a good solution for this. Therefore, the heterogeneous network control system that integrates wireless network and wired network is an inevitable trend to solve complex process industrial measurement and control.

The concept of industrial wireless technology was first proposed by the US Department of Energy in 2002. Industrial wireless technology is an emerging wireless communication technology for information interaction between devices. It is suitable for use in harsh industrial field environments. It has technical characteristics such as strong anti-interference ability, low energy consumption, and good real-time communication.

At present, the wireless technologies used in the field of industrial automation mainly focus on WLAN/IEEE802.11, BlueTooth/IEEE802.15.1 and ZigBee/IEEE802.15.4. In the research, it is found that the traditional IEEE802.11 wireless communication network is designed for the office environment, and its physical layer transmission mechanism, such as WLAN's DSSS (Direct Sequence Spread Spectrum) technology, has a high transmission rate and is suitable for high-speed large data throughput. Network applications have high energy consumption and poor anti-interference performance. They are not suitable for many industrial control application nodes. They must be improved in the physical layer, MAC layer, and protocol model to provide reliable real-time services. The FSSS (frequency modulation spread spectrum) mechanism of Bluetooth does not improve the above problems obviously, and the number of nodes in each cell is only 7, which is only suitable for some special industrial applications. IEEE 802.15.4 technology has good advantages and development prospects in short-distance, small-volume wireless sensor network applications, but in harsh process industrial environment applications, the network protocol needs to be improved to reduce spatial reflection, Delay and packet loss problems caused by frequency interference, etc.

At present, the new generation of short-distance wireless digital transmission technology is CSS (Chirp Spread Spectrum, broadband chirp spread spectrum, also referred to as Chirp spread spectrum), this modulation method combines the advantages of FSK, PSK and ASK three methods, which can be very effective It can effectively suppress various noise and multipath interference in the industrial environment. The power consumption required for each bit transmission is 1/6 of IEEE802.11b and 1/60 of Bluetooth. Its data transmission rate can reach up to 2Mbps, the outdoor propagation loss distance can reach 900m, and the receiving sensitivity is -92dBm/Mbps. Therefore, CSS-based IEEE802.15.4a has been voted and approved as IEEE's latest international communication standard for industrial wireless control in October 2006 (officially promulgated in July 2007). Simply put, CSS technology plus IEEE802.15.4 MAC protocol and networking rules constitute an improved IEEE802.15.4a, which is especially suitable for use in industrial automation field equipment layer control networks, with low cost, high speed, and low power consumption. superiority.

The utility model patent "EPA standard-based wireless handheld terminal" (application number 200620110844.2) submitted by Wang Ping and others in 2006 combined wireless technology and EPA standards, designed a wireless handheld terminal based on EPA standards, and introduced 802.11b wireless networks into the industrial site. The invention patent "multi-protocol industrial Ethernet adapter" (application number 200710171777.4) submitted by Liu Jian and others in 2008 provides a multi-protocol industrial Ethernet adapter as an independent interface product, suitable for communication nodes, protocol conversion device and protocol gateway aspects. However, in the published patent literature, there is no method and device related to introducing the 802.15.4a industrial wireless network to the MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus.

Contents of the invention

The object of the present invention is to provide a multi-protocol gateway and a protocol conversion method for introducing MODBUS/TCP industrial Ethernet and FROFIBUS-DP field bus into an IEEE802.15.4a-based industrial wireless network for the defects in the prior art.

The present invention not only considers the present situation that the current wired field bus/industrial Ethernet is the mainstay, but also takes into account the seamless connection with the frontier technology of the wireless network. It aims to realize a wired/wireless heterogeneous control network gateway that meets industrial real-time requirements and open data communication, builds a universal protocol conversion mechanism, and enables sensors, transmitters, and actuators with wired or wireless network interfaces on site Smart devices can be connected to a unified system protocol framework, thus laying the foundation for the realization of enterprise comprehensive automation including the bottom real-time information.

The IEEE802.15.4a involved in the present invention is a new type of industrial wireless local area network standard. In terms of characteristics, this new type of wireless network can be described as a mixture of ZigBee and RFID, and belongs to a kind of ultra wide band wireless technology (Ultra Wide Band, UWB) . UWB wireless technology is the most advanced wireless communication technology with short distance, bandwidth above 1GHz and low signal power spectral density.

PROFIBUS-DP complies with EN50170 European standard and complies with IEC1158-2 standard. It is specially designed for communication between automation system and equipment-level distributed I/O, and is mainly used for high-speed data transmission of distributed control system. It adopts the physical layer in the OSI model, and the data link layer includes the basic functions of ROFIBUS-DP and the user interface of the profile.

MODBUS/TCP is an extension of MODBUS. The physical layer and data link layer of the protocol are based on Ethernet and standard TCP/IP protocol, while the definition of the application layer is common to other protocols in the MODBUS protocol family. It defines a simple, open and widely used transport protocol for master-slave communication.

IEEE802.15.4a industrial wireless network standard, PROFIBUS-DP field bus protocol and MODBUS/TCP industrial Ethernet protocol adopt different specifications in the physical layer, and use different media access methods in the data link layer. In order to realize the intercommunication between these three networks, the multi-protocol gateway must not only meet the requirements of the physical layer and data link layer of the three protocols, but also be able to explain the definitions of different application layers.

In order to achieve the above object, design of the present invention is:

The present invention realizes the multi-protocol gateway and protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus: it adopts AT91RM9200 microprocessor as the core control chip, and the chip integrates Ethernet controller, USB controller; by expanding the DM9161EP Ethernet physical layer interface chip, and writing the MODBUS/TCP master station program, so as to realize a MODBUS/TCP master station module. The microprocessor is connected with the Siemens SPC3 protocol chip through the internal bus to realize a PROFIBUS-DP slave station module. The SPC3 protocol chip integrates all protocols of PROFIBUS-DP, which can greatly reduce the load of the connected microprocessor. The microprocessor is connected with the NA1TR8 wireless chip through the SPI bus, and the wireless master station program is written, so as to realize a wireless master station module and successfully connect the IEEE802.15.4a wireless network. And through the whole system through the unified protocol conversion model, the protocol conversion between "two masters and one slave" is realized.

In this protocol conversion model, IEEE802.15.4a wireless network and MODBUS/TCP industrial Ethernet each have a master station, both exist at the same time, they can independently complete the corresponding functions, and the two are equal to each other. Each master station has its own polling cycle. The system establishes a data copy area for each master station. The data information of the slave nodes that need to be converted is stored in this data copy area and corresponds one by one. When each master station polls this type of site, it maps the acquired data or the data to be written into the corresponding copy area. Through the data copy area and address conversion technology, the master station can access the data of the other slave station, and the two master stations can access each other's data. For PROFIBUS slave stations, both master stations can access its data area.

In order to enable the two master stations (A network and B network) in the system to independently access all sub-nodes, it is first necessary to convert the address of the message, that is, use the gateway to convert the address of the sub-node in the B network to A website address. An address conversion mapping area is opened in the memory of the gateway, and the corresponding relationship between the addresses of each sub-node and other network master stations is stored in advance. When receiving a message that needs to be converted, it compares and searches in the address conversion mapping area, and converts the target address into the corresponding B network address according to the mapping relationship. Do the same for the slave station (C network). Specific steps are as follows:

(1) Open up a memory area in the microprocessor memory as an address translation mapping area.

(2) Establish a structure array according to IEEE802.15.4a network and MODBUS/TCP network respectively.

(3) According to the network configuration parameters, initialize the structure array, and establish the corresponding relationship between the nodes of each network.

(4) According to the address of the current message, compare and search in the address translation mapping area.

(5) Repackage the new target address according to the mapping relationship.

The main program flow of the system is: after the system is powered on, the microprocessor is initialized, the configuration parameters are read in, the wireless master module, the MODBUS/TCP master module and the PROFIBUS-DP slave module are initialized, the address conversion mapping area is initialized, the data The replica area is initialized and enters the process of data interaction and protocol conversion. After that, if no abnormal situation occurs, the system will always be in the state of data interaction and protocol conversion.

The protocol conversion process is as follows:

First, the master station polls the MODBUS/TCP network. If the message belongs to its own network, it can directly send the message for operation.

If the packet belongs to a wireless protocol station, perform address translation. If it is normal message forwarding, the operation to be performed to analyze the message. If it is a read operation, it will directly read the data in the data output copy area of the protocol, and return a message response, and the child node will update the data in the output area during the polling cycle of the protocol; if it is a write operation, it will write the data into the data Enter the copy area, return the corresponding message, and this part of the data will be written to the corresponding child node in the polling cycle of the protocol. If the urgent message is forwarded, after the address conversion is completed, the corresponding child node of the protocol is directly operated and returned, and the data copy area of the protocol is updated.

If the message belongs to the PROFIBUS-DP slave station, the address conversion is performed, and the dual-port RAM in the slave station module is directly read and written, and its data update depends on the polling cycle of the PROFIBUS master station.

The above protocol conversion process assumes that the MODBUS/TCP master station polled the status of other nodes at that time. If the wireless master station polls the status of other nodes, it also follows the corresponding process, just swap the positions of the two master stations. . The PROFIBUS-DP slave station only serves as the slave station station of the above two master stations, and does not perform polling.

According to above-mentioned inventive concept, the present invention adopts following technical scheme:

A multi-protocol gateway based on IEEE802.15.4a industrial wireless network accessing MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus, including microprocessor, MODBUS/TCP master station, IEEE802.15.4a wireless master station, PROFIBUS -DP slave station, externally expanded SDRAM memory and FLASH memory, RJ45 network port, 485 physical layer interface, USB interface; it is characterized in that the connection mode of the circuit is centered on the microprocessor, and the MODBUS/MODBUS is connected through the MDIO interface The DM9161 EP Ethernet physical layer interface chip of the TCP master station is connected to the protocol chip SPC3 of the PROFIBUS-DP slave station, the SDRAM memory and the FLASH memory through an internal bus, and connected to the IEEE802.15.4a wireless The NA1TR8 protocol chip of the master station, with an externally expanded USB interface.

The multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus, using the above-mentioned IEEE802.15.4a-based industrial wireless network access MODBUS/TCP industrial Ethernet and The multi-protocol gateway of the PROFIBUS-DP field bus performs protocol conversion, the IEEE802.15.4a wireless protocol is realized by the IEEE802.15.4a wireless master station, the MODBUS/TCP protocol is realized by the MODBUS/TCP master station, and the PROFIBUS-DP slave station is realized by the PROFIBUS-DP DP protocol, the microprocessor realizes the protocol conversion among the three kinds of networks, and its specific steps are as follows:

1) Microprocessor initialization;

2) Copy the program code from the FLASH memory to the SDRAM memory to run;

3) The microprocessor reads in the network configuration parameters through USB;

4) MODBUS/TCP master module initialization;

5) IEEE802.15.4a wireless master station module initialization;

6) PROFIBUS-DP slave module initialization;

7) Open up a structure array for address translation, and initialize the address translation mapping area according to the instructions of the network parameters;

8) Initialize the data copy area in the MODBUS/TCP master station and the wireless master station;

9) MODBUS/TCP master station polling and protocol conversion;

10) Wireless master station polling and protocol conversion based on IEEE802.15.4a;

11) PROFIBUS-DP slave station polling and protocol conversion;

12) Return to step 9), and run in a loop.

Compared with the prior art, the present invention has the following outstanding features and significant progress:

1. The SPI interface of the microprocessor is connected with the NA1TR8 protocol chip, realizing the introduction of IEEE802.15.4a industrial wireless network into the system structure of MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus.

2. There are two master stations in the system, which can work independently and in parallel as master stations at the same time, and can also be configured as a master-slave relationship. The system can run stably in the above two cases.

3. The multi-protocol gateway based on IEEE802.15.4a industrial wireless network accessing MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus realizes the address conversion technology based on the mapping relationship, so that the two master stations can access each other equally of slave nodes.

Description of drawings:

FIG. 1 is a schematic diagram of a hardware platform of an embodiment of the present invention.

Fig. 2 is a flow chart of the main program of the multi-protocol gateway in the embodiment of the present invention.

Fig. 3 is a flow chart of the MODBUS/TCP Ethernet initialization configuration subroutine of the embodiment of the present invention.

Fig. 4 is a flow chart of the wireless network initialization configuration subroutine of the embodiment of the present invention.

Fig. 5 is a flow chart of the PROFIBUS-DP initialization configuration subroutine of the embodiment of the present invention.

FIG. 6 is a schematic structural diagram of address translation according to an embodiment of the present invention.

Fig. 7 is a unified message model diagram of the embodiment of the present invention

Fig. 8 is a polling flowchart of the MODBUS/TCP master station according to the embodiment of the present invention.

FIG. 9 is a polling flowchart of an IEEE802.15.4a wireless master station according to an embodiment of the present invention.

Detailed ways:

A preferred embodiment of the present invention is described below in conjunction with accompanying drawing:

其电路的连接方式是以微处理器①为中心，通过MDIO接口⑩外扩DM9161 EP以太网物理层接口芯片③，通过内部总线⑨连接PROFIBUS-DP协议芯片SPC35，通过SPI总线

连接NA1TR8无线协议芯片②，外扩USB接口

See Figure 1, this multi-protocol gateway for accessing MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus based on IEEE802.15.4a industrial wireless network, including microprocessor①, MODBUS/TCP master station, IEEE802.15.4a wireless Master station, PROFIBUS-DP slave station, externally expanded SDRAM memory ⑦ and FLASH memory ⑧, RJ45 network port ④, 485 physical layer interface ⑥, USB interface

The connection method of the circuit is centered on the microprocessor ①, through the MDIO interface ⑩, the DM9161 EP Ethernet physical layer interface chip ③ is externally expanded, and the PROFIBUS-DP protocol chip SPC35 is connected through the internal bus ⑨, and the SPI bus

Connect the NA1TR8 wireless protocol chip ②, expand the USB interface

与NA1TR8无线协议芯片②连接，形成一个无线主站模块，无线网络与无线子节点

互联。无线协议芯片采用了宽带线性调频扩频(Chirp Spread Spectrum)技术作为实现工业无线网络协议IEEE802.15.4a的基准物理层标准。此外，无线协议芯片含有ISM通带滤波器以提高抗干扰性，用户可以在500kbps、1Mbps和2Mbps中选择适合的数据传输率。Adopt AT91RM9200 microprocessor ① as the core control chip of the system. Microprocessor ① via SPI bus

Connect with NA1TR8 wireless protocol chip ② to form a wireless master station module, wireless network and wireless child nodes

interconnected. The wireless protocol chip adopts the broadband chirp spread spectrum (Chirp Spread Spectrum) technology as the reference physical layer standard for realizing the industrial wireless network protocol IEEE802.15.4a. In addition, the wireless protocol chip contains an ISM passband filter to improve anti-interference, and users can choose the appropriate data transmission rate among 500kbps, 1Mbps and 2Mbps.

The AT91RM9200 microprocessor ① integrates the Ethernet controller, and expands the DM9161EP Ethernet physical layer interface chip ③ through the MDIO interface ⑩. Its functions include physical coding sublayer, physical media attachment, twisted pair physical media sublayer, 1OBASE-TX coder/decoder and twisted pair media access unit, etc. The interface chip communicates with other MODBUS sub-nodes through the RJ45 network port ④ Communicate to form a MODBUS/TCP master module.

AT91RM9200 microprocessor ① connects with PROFIBUS protocol chip SPC3 ⑤ through internal bus ⑨, and adds 485 physical layer interface ⑥ to form a PROFIBUS-DP slave station module. The SPC3 chip includes all DP protocols, can independently complete all communication protocols, and can be used for up to 12Mbps bus. The microprocessor operates the SPC3 chip just like operating its internal RAM.

连接，用于基于PC机的软件配置。AT91RM9200 microprocessor ① externally expands SDRAM memory ⑦ and FLASH memory ⑧, the former stores the code of program operation, and the latter stores the data collected on site. When the task is running, the program code will be copied from the FLASH memory to the SDRAM memory for operation, improving the system speed. Microprocessor ① also with USB interface

connection for PC-based software configuration.

Referring to Figure 2, this multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access to MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus adopts the above-mentioned IEEE802.15.4a-based industrial wireless network access to MODBUS/TCP The multi-protocol gateway of TCP industrial Ethernet and PROFIBUS-DP field bus performs protocol conversion, the IEEE802.15.4a wireless master station implements the IEEE802.15.4a wireless protocol, the MODBUS/TCP master station implements the MODBUS/TCP protocol, and the PROFIBUS-DP slave The station implements the PROFIBUS-DP protocol, and the microprocessor realizes the protocol conversion between the three networks, and the specific steps are as follows:

1) Microprocessor ① initialization;

2) Copy the program code from the FLASH memory ⑧ to the SDRAM memory ⑦ to run;

3) The microprocessor ① reads in the network configuration parameters through the USB interface;

4) MODBUS/TCP master module initialization;

5) IEEE802.15.4a wireless master station module initialization;

6) PROFIBUS-DP slave module initialization;

7) Open up a structure array for address translation, and initialize the address translation mapping area according to the instructions of the network parameters;

8) Initialize the data copy area in the MODBUS/TCP master station and the wireless master station;

9) MODBUS/TCP master station polling and protocol conversion;

10) Wireless master station polling and protocol conversion based on IEEE802.15.4a;

11) PROFIBUS-DP slave station polling and protocol conversion;

12) Return to step 9), and run in a loop.

Referring to Figure 3, before the MODBUS/TCP Ethernet master module works normally, it needs to be initialized, including initializing the EMAC interface of the AT91RM9200 microprocessor ①, and then resetting the DM9161EP Ethernet physical interface chip ③. Initialize the DM9161EP Ethernet physical interface chip ③ through the MDIO interface of the AT91RM9200 microprocessor ①, configure the mode control register, and enable the receiving/sending interrupt of the EMAC. Finally, enter the protocol main program to make the MODBUS/TCP master module work normally. The specific initialization steps are as follows:

(1) Initialize the EMAC interface in the AT91RM9200 microprocessor ①;

(2) Reset the DM9161EP Ethernet physical layer interface chip ③ through the microprocessor ①;

(3) Initialize the DM9161EP Ethernet physical layer interface chip ③ through the MDIO interface of the microprocessor ①, configure the mode control register in the Ethernet physical layer interface chip Ethernet physical layer interface chip;

(4) Enable the receiving/sending interrupt of EMAC by the microprocessor ①;

(5) Enter the MODBUS/TCP protocol entry program, so that the MODBUS/TCP master station enters the normal operation state.

Referring to Figure 4, before the wireless master module works normally, it is necessary to initialize the NA1TR8 protocol chip ②, including initializing the SPI interface of the AT91RM9200 microprocessor ①, and then reset the NA1TR8 wireless protocol chip ②. Send the big and small endian synchronization words, enable the internal clock of the chip at the same time, configure the access mode of the register, set the data retransmission mechanism, enable the receive/send interrupt, etc. Finally, start the wireless chip to make the master station start to run normally. The specific initialization steps are as follows:

(1) Initialize the SPI interface in the AT91RM9200 microprocessor ①;

(2) Reset the NA1TR8 wireless protocol chip ② through the microprocessor ①;

(3) The microprocessor 1. sends a synchronization word, so that the wireless protocol chip 2. and the data size of the microprocessor 1. are synchronized;

(4) Enable the internal clock of the wireless protocol chip through the microprocessor ①, configure the access mode of the registers in the wireless protocol chip, set the data retransmission mechanism, enable receiving/sending interrupts, etc.;

(5) The parameters of the wireless master station are configured by the program;

(6) Start the NA1TR8 wireless protocol chip ②, and the wireless master station enters the normal operation state.

Referring to Figure 5, the PROFIBUS-DP slave interface is still offline after power-on and cannot receive any messages. For this reason, the SPC3 protocol chip ⑤ must be initialized, and the configuration of the basic information and function-related registers of the slave station must be completed. SPC3 Protocol chip ⑤ Calculation of internal data buffer pointers and various definitions related to external interrupts. After power on, the SPC3 protocol chip ⑤ will get a reset pulse, thus entering the reset mode. Then initialize to set the enable interrupt, write slave station identification number and address, on-chip mode register, diagnosis buffer, parameter buffer, configuration buffer, address buffer, initial length, and calculate each The pointer of the buffer and the pointer of the auxiliary buffer determine the input/output buffer and the pointer according to the length of the transmitted data, open the interrupt, etc., and then send a start command to the SPC3 protocol chip ⑤. The specific initialization steps are as follows:

(1) Initialize the internal bus interface of the AT91RM9200 microprocessor ①;

(2) The interrupt permission of the SPC3 protocol chip ⑤ is set by the program, and the slave station identification number and address are written;

(3) the mode register of the SPC3 protocol chip 5. is set by the program, and the length and other parameters of the diagnostic buffer, the parameter buffer, the configuration buffer, the address buffer are set;

(4) get the pointer of each buffer zone and the pointer of auxiliary buffer zone according to above initial value;

(5) Enter the main program of the PROFIBUS-DP slave station, and the slave station enters the normal operation state.

Referring to FIG. 6 , the specific implementation of the structure array opened for address translation: first, a structure array is opened for different networks. Among them, the first data of the structure in the structure array is the slave station address of the current network, and the second data is a pointer. According to the configuration parameters of the network, it points to the structure address of the corresponding slave station address of another network, such as the network If there is no corresponding slave station, it will directly point to empty.

Referring to Fig. 7, the unified message model of the multi-protocol gateway based on the IEEE802.15.4a industrial wireless network accessing MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus is: firstly, the first two bytes are defined by the message The address of the slave station involved; the third byte is the state of the message, 00 is an ordinary message, 01 is an emergency message; the latter is a message, and the byte length is different according to the message, and the last two bytes It is the end character of the message, which is FE, FD.

Referring to Figure 8, there is a protocol conversion program written in the AT91RM9200 microprocessor ① to realize the protocol conversion between different networks. The polling cycle of the whole system consists of three parts: the MODBUS/TCP master station polls the child nodes in its own network, then polls the wireless master station, and finally polls the PROFIBUS-DP slave station.

The polling and protocol conversion steps by the MODBUS/TCP master station are:

1. The MODBUS/TCP master station receives the message, and judges whether the target address of the message is in the same network, and if so, sends the message directly for operation; if not, the MODBUS/TCP master station polls the Node, update the data copy area;

2. The MODBUS/TCP master station polls the wireless master station. If the wireless master station does not receive the message, it polls the wireless sub-node, updates the data copy area, and goes to step (5) to continue; if the wireless master station receives the message file, obtain the network source address and destination address, and wait for address translation;

3. Read the structure array in the address conversion mapping area of the microprocessor, and perform corresponding conversion according to the content of the array;

4. After the address conversion is completed, the MODBUS/TCP master judges the nature of the message:

A. If it is a normal message: Operate the input/output data copy area of the wireless master station and return a message response. In the next polling cycle, the data in the input area of the wireless master station will be written to the child nodes, and the data in the output area of the wireless master station will be updated;

B. If it is an emergency message: the wireless master station directly performs corresponding operations on the child nodes and returns a message response;

5. The MODBUS/TCP master station polls the PROFIBUS-DP slave station. If the PROFIBUS-DP slave station does not receive the message, it does not perform any operations; RAM operates accordingly. The data in the dual-port RAM will be updated at any time according to the polling time of the slave station by the PROFIBUS master station;

6. After the polling of the MODBUS/TCP master station is over, enter the status of the wireless master station to poll each child node.

Referring to Figure 9, the steps of polling and protocol conversion by the wireless master station are:

(1) The wireless master station receives the message, and judges whether the target address of the message is in the same network, and if so, sends the message directly for operation; if not, the wireless master station polls the wireless network child nodes and updates the data copy area ;

(2) The wireless master station polls the MODBUS/TCP master station. If the MODBUS/TCP master station does not receive the message, it polls the MODBUS/TCP sub-node, updates the data copy area, and goes to step (5) to continue; if the MODBUS/TCP master station The TCP master station receives the message, obtains the network source address and destination address, and waits for address translation;

(3) read the structure array in the address conversion mapping area in the microprocessor, and carry out corresponding conversion according to the array content;

(4) After the address conversion is completed, the wireless master station judges the nature of the message:

A. If it is an ordinary message: Operate the input/output data copy area of the MODBUS/TCP master station, and return a message response. In the next polling cycle, the data in the input area of the MODBUS/TCP master station will be written to the child nodes, and the data in the output area of the MODBUS/TCP master station will be updated;

B. If it is an urgent message: the MODBUS/TCP master station directly performs corresponding operations on the child nodes and returns a message response;

(5) The MODBUS/TCP master station polls the PROFIBUS-DP slave station. If the PROFIBUS-DP slave station does not receive the message, no operation is performed; if the PROFIBUS-DP slave station receives the message, it port RAM for corresponding operations. The data in the dual-port RAM will be updated at any time according to the polling time of the slave station by the PROFIBUS master station;

(6) The polling of the wireless master station ends, and the MODBUS/TCP master station polls the status of each child node.

For example, the MODBUS/TCP master station receives the following message:

The MODBUS/TCP master station queries the structure array in the address conversion mapping area, and the pointer points to the slave station address of the wireless master station to complete the address conversion. Analyze the content of the message, where 00 00 represents the node number, 03 the function number represents the read operation, 00 00 represents the starting address, 01 represents the byte length, and the message status 00 is an ordinary message. Directly read the data in the copy area of the wireless slave station. If the status of the message is 01, which is an urgent message, the message will be reconverted into a wireless message: 00 04 01 01, 00 represents the node number, 04 the function number represents the read operation, 01 represents the byte length, and 01 represents the start start address. Obtain the data of the wireless slave station directly through wireless, and update the corresponding data copy area.

Claims (9)

1. A multi-protocol gateway based on IEEE802.15.4a industrial wireless network accessing MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus, including microprocessor ①, MODBUS/TCP master station, IEEE802.15.4a wireless master station, PROFIBUS-DP slave station, externally expanded SDRAM memory ⑦ and FLASH memory ⑧, RJ45 network port ④, 485 physical layer interface ⑥, USB interface

It is characterized in that the connection mode of the circuit is centered on the microprocessor ①, connected to the DM9161 EP Ethernet physical layer interface chip ③ of the MODBUS/TCP master station through the MDIO interface ⑩, and connected to the PROFIBUS- The protocol chip SPC3 of the DP slave station, the SDRAM memory ⑦ and the FLASH memory ⑧, through the SPI bus

Connect the NA1TR8 protocol chip ② of the IEEE802.15.4a wireless master station, and the microprocessor ① expands the USB interface

The microprocessor (1) adopts AT91RM9200 as the core chip, and the program code and data are stored in the FLASH. When the task is running, the program code will be copied to the SDRAM to run, so as to improve the system speed. 2. A multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus, adopting the industrial wireless network access based on IEEE802.15.4a described in claim 1 Multi-protocol gateway into MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus for protocol conversion, characterized in that the IEEE802.15.4a wireless protocol is realized by the IEEE802.15.4a wireless master station, and the MODBUS/TCP is realized by the MODBUS/TCP master station Protocol, the PROFIBUS-DP slave station implements the PROFIBUS-DP protocol, and the microprocessor controls the protocol conversion between the three networks. The specific steps are as follows: 1) Microprocessor ① initialization; 2) Copy the program code from the FLASH memory ⑧ to the SDRAM memory ⑦ to run; 3) The microprocessor ① reads in the network configuration parameters through the USB interface; 4) MODBUS/TCP master module initialization; 5) IEEE802.15.4a wireless master station module initialization; 6) PROFIBUS-DP slave module initialization; 7) Create a structure array for address translation, and initialize the address translation mapping area according to network parameters 8) Data copy area initialization in MODBUS/TCP master station and IEEE802.15.4a wireless master station; 9) MODBUS/TCP master station polling and protocol conversion; 10) Wireless master station polling and protocol conversion based on IEEE802.15.4a; 11) PROFIBUS-DP slave station polling and protocol conversion; 12) Return to step 9), and run in a loop. 3. the multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus as claimed in claim 2, is characterized in that described step 4) MODBUS/TCP The steps to initialize the master station module are: (1) Initialize the EMAC in the AT91RM9200 microprocessor ①; (2) Reset the DM9161EP Ethernet physical layer interface chip ③ through the microprocessor ①; (3) Initialize the DM9161EP Ethernet physical layer interface chip ③ through the MDIO interface of the microprocessor ①, and configure the mode control register in the Ethernet physical layer interface chip; (4) Enable the receive/transmit interrupt of EMAC; (5) Enter the MODBUS/TCP protocol entry program, so that the MODBUS/TCP master station enters the normal operation state. 4. the multi-protocol conversion method of the industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus based on IEEE802.15.4a as claimed in claim 2, it is characterized in that described step 5) IEEE802.15.4 a The steps to initialize the wireless master station module are: (1) Initialize the SPI interface in the AT91RM9200 microprocessor ①; (2) Reset the NA1TR8 protocol chip ② through the microprocessor ①; (3) Microprocessor ① sends synchronous word, makes NA1TR8 protocol chip ② and microprocessor ① data size end synchronization; (4) Enable the internal clock of the NA1TR8 protocol chip ② through the microprocessor ①, configure the access mode of the registers in the NA1TR8 protocol chip ②, set the data retransmission mechanism, and enable receiving/sending interrupts; (5) Configure the parameters of the IEEE802.15.4a wireless master station by the program; (6) Start the NA1TR8 protocol chip ②, and the IEEE802.15.4a wireless master station enters the normal operation state. 5. the multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus as claimed in claim 2, is characterized in that described step 6) PROFIBUS-DP The steps for slave module initialization are: (1) Initialize the internal bus interface ⑨ of the AT91RM9200 microprocessor ①; (2) The interrupt permission of the SPC3 protocol chip ⑤ is set by the program, and the slave station identification number and address are written; (3) The mode register of the SPC3 protocol chip ⑤ is set by the program, and the length of the diagnostic buffer, the parameter buffer, the configuration buffer and the address buffer is set; (4) get the pointer of each buffer zone and the pointer of auxiliary buffer zone according to above initial value; (5) Enter the main program of the PROFIBUS-DP slave station, and the PROFIBUS-DP slave station enters the normal operation state. 6. the multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial ethernet and PROFIBUS-DP field bus as claimed in claim 2, it is characterized in that the address conversion mapping of described step 7) The steps for area initialization are as follows: (1) Open up a piece of memory area in the microprocessor memory as the address translation mapping area; (2) Establish a structure array for IEEE802.15.4a wireless network, MODBUS/TCP network and PROFIBUS-DP network respectively; (3) The microprocessor ① initializes the structure arrays respectively according to the configuration parameters of each network. 7. the multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus as claimed in claim 2, is characterized in that described step 9) MODBUS/TCP The steps of master station polling and protocol conversion are: (1) The MODBUS/TCP master station receives the message, and judges whether the target address of the message is in the same network, if so, directly sends the message for operation; if not, the MODBUS/TCP master station polls the MODBUS/TCP network Child node, update the data copy area; (2) The MODBUS/TCP master station polls the IEEE802.15.4a wireless master station. If the IEEE802.15.4a wireless master station does not receive the message, it polls the wireless sub-node, updates the data copy area, and goes to step (5) Continue; if the IEEE802.15.4a wireless master station receives the message, obtain the network source address and destination address, and wait for address translation; (3) read the structure array in the address conversion mapping area in the microprocessor, and carry out corresponding conversion according to the array content; (4) After the address conversion is completed, the MODBUS/TCP master judges the nature of the message: A. If it is an ordinary message: operate the input/output data copy area of the IEEE802.15.4a wireless master station, and return a message response; in the next polling cycle, the data in the input area of the IEEE802.15.4a wireless master station will be Write to the child node, the data in the output area of the IEEE802.15.4a wireless master station will be updated; B. If it is an emergency message: the IEEE802.15.4a wireless master station directly performs corresponding operations on the child nodes and returns a message response; (5) The MODBUS/TCP master station polls the PROFIBUS-DP slave station. If the PROFIBUS-DP slave station does not receive the message, no operation is performed; if the PROFIBUS-DP slave station receives the message, it The data in the dual-port RAM will be updated at any time according to the polling time of the slave station by the PROFIBUS master station; (6) The polling of the MODBUS/TCP master station is over, and the wireless master station enters the state of polling each child node. 8. The multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus as claimed in claim 2, said step 10) of its feature is based on IEEE802.15.4a The steps of wireless master station polling and protocol conversion are as follows: (1) The IEEE802.15.4a wireless master station receives the message, and judges whether the target address of the message is in the same network. Network child nodes, update the data copy area; (2) The IEEE802.15.4a wireless master station polls the MODBUS/TCP master station. If the MODBUS/TCP master station does not receive the message, it polls the MODBUS/TCP sub-node, updates the data copy area, and goes to step (5) to continue ; If the MODBUS/TCP master station receives the message, obtain the network source address and destination address, and wait for the address conversion; (3) read the structure array in the address conversion mapping area in the microprocessor, and carry out corresponding conversion according to the array content; (4) After the address conversion is completed, the IEEE802.15.4a wireless master station judges the nature of the message: A. If it is an ordinary message: operate the input/output data copy area of the MODBUS/TCP master station, and return a message response; in the next polling cycle, the data in the input area of the MODBUS/TCP master station will be written to the child node , the data in the output area of the MODBUS/TCP master station will be updated; B. If it is an urgent message: the MODBUS/TCP master station directly performs corresponding operations on the child nodes and returns a message response; (5) The wireless master station polls the PROFIBUS-DP slave station. If the PROFIBUS-DP slave station does not receive the message, no operation is performed; Perform corresponding operations; the data in the dual-port RAM will be updated at any time according to the polling time of the slave station by the PROFIBUS master station; (6) The polling of the IEEE802.15.4a wireless master station is over, and the MODBUS/TCP master station is in the state of polling each child node. 9. The multi-protocol conversion method based on IEEE802.15.4a industrial wireless network access MODBUS/TCP industrial Ethernet and PROFIBUS-DP field bus as claimed in claim 2, is characterized in that the PROFIBUS-DP of described step 11) The steps of slave station polling and protocol conversion are: (1) If the PROFIBUS-DP slave station does not receive the message, do not perform any operation and go to step (4); (2) If the PROFIBUS-DP slave station receives the message, perform corresponding operations on the dual-port RAM according to the content of the message; (3) The data in the dual-port RAM will be updated at any time according to the polling time of the slave station by the PROFIBUS master station; (4) The program returns.

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